When large surface area objects are submerged to any depth, they experience large drag forces acting much like a massive sea anchor when the supporting surface vessel responds to the sea environment. Any supporting cable from the surface vessel will experience significant amplification of the static load due to the surface vessel's motion.
Further, the vessel(s), cable and submerged object forms a “spring-mass-damper” system having a natural period that may be excited by the sea forcing motion of the surface vessels at the system's natural frequency. This creates a zone of resonance where the cable length tunes the system's natural frequency to that of the supporting vessel motion.